Execute method on startup in Spring

Question

Is there any Spring 3 feature to execute some methods when the application starts for the first time  I know that I can do the trick of setting a method with  Scheduled annotation and it executes just after the startup  but then it will execute periodically

User · Answer

For Java 1 8 users that are getting a warning when trying to reference the  PostConstruct annotation  I ended up instead piggybacking off the  Scheduled annotation which you can do if you already have an  Scheduled job with fixedRate or fixedDelay   import org slf4j Logger  import org slf4j LoggerFactory  import org springframework scheduling annotation EnableScheduling  import org springframework scheduling annotation Scheduled  import org springframework stereotype Component    EnableScheduling  Component public class ScheduledTasks    private static final Logger LOGGER   LoggerFactory getLogger ScheduledTasks class    private static boolean needToRunStartupMethod   true        Scheduled fixedRate   3600000      public void keepAlive               log  alive  every hour for sanity checks         LOGGER debug  alive            if  needToRunStartupMethod                runOnceOnlyOnStartup                needToRunStartupMethod   false                       public void runOnceOnlyOnStartup             LOGGER debug  running startup job

User · Answer

If by  application startup  you mean  application context startup   then yes  there are many ways to do this  the easiest  for singletons beans  anyway  being to annotate your method with  PostConstruct  Take a look at the link to see the other options  but in summary they are    Methods annotated with  PostConstruct afterPropertiesSet   as defined by the InitializingBean callback interface A custom configured init   method   Technically  these are hooks into the bean lifecycle  rather than the context lifecycle  but in 99  of cases  the two are equivalent   If you need to hook specifically into the context startup shutdown  then you can implement the Lifecycle interface instead  but that s probably unnecessary

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Posted another solution that implements WebApplicationInitializer and is called much before any spring bean is instantiated  in case someone has that use case  Initialize default Locale and Timezone with Spring configuration

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What we have done was extending org springframework web context ContextLoaderListener to print something when the context starts   public class ContextLoaderListener extends org springframework web context ContextLoaderListener       private static final Logger logger   LoggerFactory getLogger  ContextLoaderListener class         public ContextLoaderListener                 logger info   Starting application                  Configure the subclass then in web xml    lt listener gt       lt listener-class gt          com mycomp myapp web context ContextLoaderListener      lt  listener-class gt   lt  listener gt

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This is easily done with an ApplicationListener  I got this to work listening to Spring s ContextRefreshedEvent   import org springframework context ApplicationListener  import org springframework context event ContextRefreshedEvent  import org springframework stereotype Component    Component public class StartupHousekeeper implements ApplicationListener lt ContextRefreshedEvent gt        Override   public void onApplicationEvent final ContextRefreshedEvent event           do whatever you need here          Application listeners run synchronously in Spring  If you want to make sure you re code is executed only once  just keep some state in your component   UPDATE  Starting with Spring 4 2  you can also use the  EventListener annotation to observe the ContextRefreshedEvent  thanks to  bphilipnyc for pointing this out    import org springframework context ApplicationListener  import org springframework context event ContextRefreshedEvent  import org springframework stereotype Component    Component public class StartupHousekeeper       EventListener ContextRefreshedEvent class    public void contextRefreshedEvent            do whatever you need here

User · Answer

If you are using spring-boot  this is the best answer   I feel that  PostConstruct and other various life cycle interjections are round-about ways  These can lead directly to runtime issues or cause less than obvious defects due to unexpected bean context lifecycle events  Why not just directly invoke your bean using plain Java  You still invoke the bean the  spring way   eg  through the spring AoP proxy   And best of all  it s plain java  can t get any simpler than that  No need for context listeners or odd schedulers    SpringBootApplication public class DemoApplication        public static void main String   args            ConfigurableApplicationContext app   SpringApplication run DemoApplication class  args            MyBean myBean    MyBean app getBean  myBean             myBean invokeMyEntryPoint

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If you want to configure a bean before your application is running fully  you can use  Autowired    Autowired private void configureBean MyBean  bean        bean setConfiguration myConfiguration

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AppStartListener implements ApplicationListener        Override     public void onApplicationEvent ApplicationEvent event            if event instanceof ApplicationReadyEvent               System out print  ciao

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In Spring 4 2  you can now simply do    Component class StartupHousekeeper         EventListener ContextRefreshedEvent class      public void contextRefreshedEvent               do whatever

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You can use  EventListener on your component  which will be invoked after the server is started and all beans initialized    EventListener public void onApplicationEvent ContextClosedEvent event

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Attention  this is only advised if your runOnceOnStartup method depends on a   fully initialized spring context  For example  you wan to call a dao   with transaction demarcation   You can also use a scheduled method with fixedDelay set very high   Scheduled fixedDelay   Long MAX VALUE  public void runOnceOnStartup         dosomething        This has the advantage that the whole application is wired up  Transactions  Dao        seen in Scheduling tasks to run once  using the Spring task namespace

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For a file StartupHousekeeper java located in package com app startup   Do this in StartupHousekeeper java    Component public class StartupHousekeeper       EventListener ContextRefreshedEvent class    public void keepHouse         System out println  This prints at startup             And do this in myDispatcher-servlet java    lt  xml version  1 0  encoding  UTF-8   gt   lt beans gt        lt mvc annotation-driven   gt       lt context component-scan base-package  com app startup    gt    lt  beans gt

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With SpringBoot  we can execute a method on startup via  EventListener annotation   Component public class LoadDataOnStartUp           EventListener ApplicationReadyEvent class      public void loadData                    do something

[java] Execute method on startup in Spring

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